Synulox Palatable Drops 40 mg/ml + 10 mg/ml, Powder for Oral Suspension

Amoxicillin, Clavulanic Acid

Last verified

Veterinary medicinal product: powder for oral suspension. Distribution category: POM-V (Veterinary Medicines Regulations 2013, Schedule 3). Active substance: Amoxicillin, Clavulanic Acid.1

In short: questions and answers

Does Synulox Palatable Drops 40 mg/ml + 10 mg/ml, Powder for Oral Suspension need a prescription?
Prescription only. As stated in the registration decision.1
Which animals is Synulox Palatable Drops 40 mg/ml + 10 mg/ml, Powder for Oral Suspension for?
Cats, Dogs.1
What is the active substance in Synulox Palatable Drops 40 mg/ml + 10 mg/ml, Powder for Oral Suspension?
Amoxicillin, Clavulanic Acid. ATCvet code: QJ01CR02.13
What is the withdrawal period of Synulox Palatable Drops 40 mg/ml + 10 mg/ml, Powder for Oral Suspension according to the leaflet?
No withdrawal period is set for this drug: it is not intended for food-producing animals.3
Dispensing
Prescription only1

POM-V: Prescription Only Medicine - Veterinarian. Supplied only on a prescription written by a veterinary surgeon who has assessed the animal.12

Supplied only on a veterinarian's prescription. As stated in the registration decision.

Animal species
Cats1, Dogs1
Active substance
Amoxicillin, Clavulanic Acid
ATCvet code
QJ01CR023
Manufacturer
Marketing authorisation holder: Zoetis UK Limited

Withdrawal period

No withdrawal period is set for this drug: it is not intended for food-producing animals.3

Summary of product characteristics

Composition

Active substance:

Each bottle of powder contains:

648 mg amoxicillin (equivalent to 743,8 mg amoxicillin trihydrate)

162 mg clavulanic acid (equivalent to 193 mg potassium clavulanate)

Each ml of reconstituted oral suspension contains:

Amoxicillin 40 mg

Clavulanic acid 10 mg

Excipients:

Qualitative composition of excipients and other constituents

Xanthan gum

Saccharin sodium

Succinic acid

Silica colloidal anhydrous

Silicon dioxide (Silica gel)

Strawberry dry flavour

Peach dry flavour

Lemon dry flavour

Powder: Off-white powder.

After reconstitution: Off-white suspension.

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Pharmacological properties

ATCvet code: QJ01CR02

Pharmacodynamics

The veterinary medicinal product is an association of amoxicillin and clavulanic acid. Amoxicillin inhibits the cross-linking of the peptidoglycan layer through a selective and irreversible blockage of various enzymes involved in this process (primarily transpeptidases) and thus prevents the formation of an intact bacterial cell wall. This results in an osmotic imbalance that particularly affects bacteria in the logarithmic phase of growth which ultimately leads to bacterial cell lysis. The effect is therefore bactericidal and related to the time the susceptible organisms are exposed to supra-minimum inhibitory concentrations. Clavulanic acid has a similar structure to beta-lactam antibiotics such as amoxicillin. It has a weak antibacterial effect but, compared to amoxicillin, has a higher affinity for beta-lactamases, enzymes produced by Gram- positive and Gram-negative bacteria which inactivate beta-lactam antibiotics through the hydrolytic cleavage of their beta-lactam ring. When administered simultaneously with amoxicillin, clavulanic acid rapidly, progressively and irreversibly inactivates the beta- lactamases by forming a stable molecule-enzyme complex. This prevents inactivation of amoxicillin by beta-lactamases and, as a result, the spectrum of amoxicillin is broadened to include strains that have acquired resistance through secretion of plasmid-derived penicillinase, and strains that are naturally resistant through the production of chromosomally mediated beta-lactamases.

Other mechanisms of resistance to beta-lactams include the modification of the antibiotic target site (penicillin-binding proteins), efflux pumps and changes in the permeability of the outer membrane.

Pharmacokinetics

Following oral administration, amoxicillin is well absorbed from the gastrointestinal tract. In dogs, bioavailability is 60-70%. Following absorption, the highest concentrations are found in the kidneys (urine), bile and further in the liver, lungs, heart, and spleen. Distribution of amoxicillin to the cerebrospinal fluid is low unless meningitis occurs. Amoxicillin is excreted mainly by the kidneys (unchanged in the urine).

Clavulanic acid is well absorbed after oral administration and has pharmacokinetic properties similar to amoxicillin. Extracellular distribution of clavulanic acid is extensive, but permeation into milk and cerebrospinal fluid is very limited. Clavulanic acid is excreted unchanged by the kidneys.

Dogs

Several studies involving 54 dogs administered the veterinary medicinal product at a dose of 10 mg amoxicillin and 2.5 mg clavulanic acid per kg of body weight showed the following results:

- For amoxicillin, the time to reach maximum concentration (Tmax) ranged from 1 to 2 hours, with a maximum concentration (Cmax) between 4.6 and 8.4 mcg/ml. The mean elimination half-life (T½) was between 0.85 and 1.42 hours.

- For clavulanic acid, the Cmax ranged from 0.32 to 2 mcg/ml, the Tmax from 0.5 to 2 hours, and the T½ from 0.59 to 0.8 hours.

Cats

Studies involving cats administered the veterinary medicinal product at a dose of 10 mg amoxicillin and 2.5 mg clavulanic acid/kg body weight showed the following results:

- For amoxicillin, the Tmax was 2 hours with a Cmax between 4.5 and 7.43 mcg/ml. The T½ was between 0.97 and 1.44 hours.

- For clavulanic acid, the Tmax was 1 hour with a Cmax ranging from 1.52 to 2.3 mcg/ml. The T½ ranged from 0.5 to 0.9 hours.

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Target species

Dogs and cats.

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Indications

Dogs:

For the treatment of

- Skin infections (including deep and superficial pyoderma).

- Soft tissue infections (including anal sacculitis and abscesses).

- Urinary tract infections.

- Respiratory infections.

- Intestinal infections.

- Periodontal infections in addition to mechanical or surgical periodontal therapy.

Cats:

For the treatment of

- Skin infections (including superficial pyoderma).

- Soft tissue infections (including abscesses).

- Urinary tract infections.

- Respiratory infections.

- Intestinal infections.

- Periodontal infections in addition to mechanical or surgical periodontal therapy.

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Dosage

Oral use.

Dosage: 10 mg amoxicillin and 2.5 mg clavulanic acid/kg body weight every 12 hours equivalent to 0.25 ml reconstituted product/kg body weight every 12 hours or 5 drops per kg body weight every 12 hours.

In refractory respiratory tract infections, the dose can be doubled to 20 mg amoxicillin and 5 mg clavulanic acid/kg body weight every 12 hours and the treatment can be prolonged for up to 10 days.

Dosing instructions:

Body weight (kg)Quantity (ml) of reconstituted veterinary medicinal product every 12 hours per dose level: 10 mg amoxicillin and 2.5 mg clavulanic acid/kgQuantity (ml) of reconstituted veterinary medicinal product every 12 hours per dose level: 20 mg amoxicillin and 5 mg clavulanic acid/kg
0.5 – 10.15 (3 drops*) to 0.25 (5 drops)0.30 (6 drops) to 0.5 (10 drops)
>1 – 20.3 (6 drops) to 0.5 (10 drops)0.6 (12 drops) to 1 (20 drops)
>2 – 30.55 (11 drops) to 0.75 (15 drops)1.1 (22 drops) to 1.5 (30 drops)
>3 – 40.8 (16 drops) to 1 (20 drops)1.6 (32 drops) to 2 (40 drops)

*1 drop delivers approximately 0.05 ml of the suspension.

Duration of treatment:

In most of the cases, a treatment duration of 5 to 7 days is sufficient.

For chronic cases, a longer course of therapy may be required.

Based on clinical trials, the following treatment durations are recommended:

Chronic skin infections, 10–20 days.

Chronic cystitis, 10–28 days.

Instructions for use:

To ensure a correct dosage, body weight should be determined as accurately as possible.

Open the bottle. Discard the original aluminium cap. Reconstitute the powder with 15 ml of tap water. Close the bottle with the dropper cap and shake vigorously to obtain a milky suspension. Open the bottle and use the dropper (graduated from 0.25 to 1 ml) to extract the prescribed amount. If needed, gently squeeze the rubber portion of the dropper to drop the excess of the veterinary medicinal product back into the bottle.

Administer the veterinary medicinal product with the graduated dropper either directly into the animal’s mouth or mixed with some food.

Shake the veterinary medicinal product well before each use.

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Contraindications

Do not use in rabbits, guinea pigs, hamsters, gerbils, chinchillas or other small herbivores.

Do not use in cases of hypersensitivity to the active substances, other substances of the beta-lactam group or to any of the excipients.

Do not administer to horses or ruminating animals.

Do not use in animals with severe renal impairment with anuria or oliguria.

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Adverse reactions

Dogs and cats:

Common (1 to 10 animals / 100 animals treated):

gastrointestinal disorder1 (e.g. vomiting, diarrhoea)

Uncommon (1 to 10 animals / 1 000 animals treated):

hypersalivation

anorexia1, 2, lethargy

Very rare (<1 animal / 10 000 animals treated, including isolated reports):

hypersensitivity reaction3 (e.g. allergic skin reaction, anaphylaxis)

1 Depending on the severity of the adverse event treatment should be discontinued and symptomatic treatment initiated based on the benefit-risk assessment by the responsible veterinarian.

2 Very rare (<1 animal / 10 000 animals treated, including isolated reports) in cats.

3 May be serious. Immediate discontinuation of the veterinary medicinal product is required. Countermeasures to be taken in case of an allergic reaction:

- anaphylaxis: administer epinephrine (adrenaline) and glucocorticoids.

- allergic skin reactions: administer antihistamines and/or glucocorticoids.

Reporting adverse events is important. It allows continuous safety monitoring of a veterinary medicinal product. Reports should be sent, preferably via a veterinarian, to either the marketing authorisation holder <or its local representative> or the national competent authority via the national reporting system. See the package leaflet for respective contact details.

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Warnings

Special precautions for safe use in the target species:

Use of the product should be based on identification and susceptibility testing of the target pathogen(s). If this is not possible, therapy should be based on epidemiological information and knowledge of susceptibility of the target pathogens at local/regional level.

Use of the product should be in accordance with official, national and regional antimicrobial policies.

An antibiotic with a lower risk of antimicrobial resistance selection (lower AMEG category) should be used for first line treatment where susceptibility testing suggests the likely efficacy of this approach.

Narrow spectrum antibiotic therapy with a lower risk of antimicrobial resistance selection should be used for first line treatment where susceptibility testing suggests the likely efficacy of this approach.

Pharmacokinetic of the active substances in the target tissue might be considered as well.

The routine use of systemic antibiotics for intestinal infections is not recommended.

Oral treatment with antibiotics can result in disturbance of gastrointestinal flora, especially in case of long-term treatment.

In case of renal or hepatic insufficiency, the use of the veterinary medicinal product should be subject to a benefit-risk assessment by the responsible veterinarian.

Special precautions to be taken by the person administering the veterinary medicinal product to animals:

Penicillins and cephalosporins may cause hypersensitivity (allergy) following injection, inhalation, ingestion, or skin contact. Hypersensitivity to penicillins can lead to cross- reactions with cephalosporins and vice versa. Allergic reactions caused by these substances may occasionally be serious.

People with known hypersensitivity to the active substance should avoid contact with the veterinary medicinal product. Wear gloves when handling this product to avoid skin contact.

In case of accidental spillage onto skin or eyes immediately wash the affected area with plenty of water.

If you develop symptoms such as a skin rash and persistent eye irritation after exposure to the veterinary medicinal product, seek medical advice immediately and show the package leaflet or label to the physician. Swelling of the face, lips, or eyes, or difficulty breathing are more serious symptoms that require urgent medical attention.

Wash hands after use.

Special precautions for the protection of the environment:

Not applicable.

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Use during pregnancy, lactation or lay

The safety of the veterinary medicinal product has not been established during pregnancy and lactation.

Pregnancy and lactation:

In laboratory studies (rat, mouse), signs of embryotoxicity or teratogenicity could only be detected at high doses.

Use only according to the benefit-risk assessment by the responsible veterinarian.

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Interactions

The bactericidal effect of amoxicillin may be inhibited by the concomitant use of bacteriostatic antimicrobials.

Penicillins may increase the effect of aminoglycosides.

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Overdose

Doses up to 40 mg amoxicillin and 10 mg clavulanic acid/kg and 60 mg amoxicillin and 15 mg clavulanic acid/kg administered twice daily for 5 days were tolerated well in young dogs and young cats respectively.

No adverse events associated with overdoses other than those listed in section 3.6 were detected in the respective studies (for information on symptomatic treatment see also section on adverse events).

Due to the neurotoxicity of penicillins, overdosing might result in central nervous system symptoms and convulsions. In these cases, treatment with the veterinary medicinal product should be discontinued immediately and symptomatic treatment should be initiated.

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Special warnings

Cross-resistance has been shown between amoxicillin/clavulanic acid and other antibiotics belonging to the beta-lactam group. Use of the veterinary medicinal product should be carefully considered when susceptibility testing has shown resistance to other antimicrobials in the beta-lactam group because its effectiveness may be reduced.

The veterinary medicinal product has no effect against infections caused by Pseudomonas spp. due to its inherent resistance.

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Withdrawal period

Not applicable.

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Incompatibilities

In the absence of compatibility studies, this veterinary medicinal product must not be mixed with other veterinary medicinal products.

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Immediate packaging

Ph. Eur. Type III clear glass bottle with nominal volume of 15 ml, closed with a metal screw cap fitted with a grey liner with a wrinkled surface composed of a chlorobutyl based compound. A dropper with graduations of 0.25 ml up to 1 ml is included. The dropper is manufactured from low density polyethylene and contains no additives.

Pack sizes: Cardboard box containing 1 x 15 ml bottle and 1 x graduated dropper.

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Storage

Do not store above 25°C.

Store the reconstituted veterinary medicinal product in a refrigerator (2°C - 8°C).

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Shelf life

Shelf life of the veterinary medicinal product as packaged for sale: 2 years.

Shelf life after reconstitution according to directions: 7 days.

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Disposal of unused product

Medicines should not be disposed of via wastewater.

Use take-back schemes for the disposal of any unused veterinary medicinal product or waste materials derived thereof in accordance with local requirements and with any national collection systems applicable to the veterinary medicinal product concerned.

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Additional information

Vm 42058/5213

8 DATE OF FIRST AUTHORISATION

20 August 1990

9 DATE OF THE LAST REVISION OF THE SUMMARY OF THE PRODUCT CHARACTERISTICS

December 2025

10 CLASSIFICATION OF VETERINARY MEDICINAL PRODUCTS

Veterinary medicinal product subject to prescription.

Detailed information on this veterinary medicinal product is available in the Union Product Database (https://medicines.health.europa.eu/veterinary).

Gavin Hall Approved: 19 December 2025

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Registration holder

Zoetis UK Limited

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Regulations

Sources

  1. VMD Product Information Database: Synulox Palatable Drops 40 mg/ml + 10 mg/ml, Powder for Oral Suspension, 42058/5213 UK Veterinary Medicines Directorate (OGL v3.0), checked 2026-10-04 archived copy from 2026-10-04
  2. The Veterinary Medicines Regulations 2013, Schedule 3 (categories of veterinary medicinal products) UK Government, legislation.gov.uk, checked 2026-10-04 archived copy from 2026-10-04
  3. Summary of Product Characteristics: Synulox Palatable Drops 40 mg/ml + 10 mg/ml, Powder for Oral Suspension UK Veterinary Medicines Directorate, SPC of the marketing authorisation holder, checked 2026-10-04 archived copy from 2026-10-04

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